Spring-jack for telephone-switchboards.



PATENTBD APR. 2l, l903 Y c. E. SGRIBNBR. Y

SPRING JACK POR TELEPHONE SWITGHBOARDS.

APPLICATION FILED JUNE Z1, 1897.

N0 MODEL.

Fgl @@@QQQQQQQ Inventor:

his Afd?? Y UNITED STATES",

PATENT OFFICE.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS7 ASSIGNOR TO ATHF. VVSTERN.ELECTRIC COMPANY, OF CIIICAGO, ILLINOIS, A CORPORATION OF ILLI- NOIS.

SPRING-JACKAV FoR'TELEPHON'EswlTcl-IBQARDS.

SPECIFICATION forming part Of Letters Patent NO. 726,105, dated April21, 1903.

Application filed June 21,1897.y Serial No. 641,669. `(No model.)

To @ZZ when@ it may concer@ Be it known that I, CHARLES E; SCRIBNER,

a citizen of the United States, residing at Chicago, in the county ofCook and State of llli nois, have invented a certain new and `useful;

in certain details of construction and dispo-` sition of parts forattaining compactness of arrangement and cheapness of construction andfor affording secure contact between .the

terminal pieces in the spring-jack and correzo sponding portionsof theplug.

My improvement applies to springjacks mounted in groups on common basesor supporting-plates, such as are usually known as strips ofspring-jacks.l In constructing 2 5 the spring-jack I provide a strip orplate of insulating material, through which I drill transverse openingsto receive the metal contact-pieces of the spring-jacks. One of thesecontact-pieces consists in a nshort tubular 3o thimble closely iittin gthe transverse opening and placed therein near one edge of the stripp.

its orifice being preferably accessibler near the front of the strip fortesting purposes. From this contact-piece an extension is led 3 5 to therear of the strip of spring-jacks through a suitably-inclined ductbetween adjacent perforations.

located in the perforationat therear of the 4o thimble before described,adapted to encircle and grasp the inserted plug, a metallic eXtensionfrom this contactipiece also being led to the rear offthe strip ofspring-jacks. The

' ing wholly avoided.

Another of the contapctfpiecesj of the jack consists in a nearlyannulagr'spring `jacl are thus located in a single drilledperforationfin the strip,"with their axes nearly concentric, and Atwoducts are provided for leading the terminals of two of thecontactfpieces to the rearL of Ythe strip, so that the operationsessential in forming the strip of `insulating material-to receive'themetallic parts of each jack, which operations ordinarily constitute themost costly processes in the construction of the spring-jack, consist 6omerely in drilling the transverse opening and ,in forming two ductsextending therefrom for each spring-jack, together with a narrow slitopening into the perforation. One of the ducts may be a narrow channelcut by means of a saw; but with these exceptions the operations offorming the insulating base-plate .consist in'drilling openings, theexpensive processes of millingand drifting openings be- Referring now tothe accompanying drawings, Which illustrate my new form of springjack,Figure l is a front elevation of a strip of ten spring-jacks. Fig. 2 isa plan of the strip, a portion containing five spring-jacks being shownin horizontal section on the center lines of the spring-jacks. Fig. 3 isarear yelevation of the strip. Fig. 4 is a transverse section of twospring-jacks on the line 4 of Fig. 2. Fig. 5 is a similar section on theline 8o f'of Fig. 2l, Fig. 6 is a perspective view of the metalliccontact-pieces ot' the spring-jack arranged in proper position relativeto each other. Fig. 7 is an elevation of the plug designed for use withthe spring-jack.

The strip or baseplate o. may be of hard rubber orA other similarinsulating material. iFor eachrspring-jack an opening ct' is drilleddeeply into the strip from the front edge. This opening meets a secondperforation a2 9o of similar diameter drilled from the rear of thestrip, the axes of this tubular opening being so disposed with relationto each other that their walls lie in the same straight line at onepoint. From therforwardext'remity 95 of the opening ct' a duct a3 ofsmall diameter is drilled obliquely downward and outward toward the rearand under surface of the strip, (with reference to Fig. 2,) meeting atransverse narrow channel a4, leading to the loo rear of the stripformed in its under surface. Sections of this duct are seen in Figs. 4and 5, while a rear View of the same appears in Fig. 3. Parallel withthe axis of the transverse perforation a2, but somewhat above the planepassing through the center lines of the spring-jacks, is a duct a5,drilled obliquely and rearwardly outward from the bottom of the openinga'. Further, a slot a0 is formed in the rear of the strip on the centerline of each opening a2, with a small lateral extension or recess a7 oneach surface of the strip. 'lhe metal parts comprised in a singlespringjack for assembly in these openings are shown in Fig. G-a thimbleb, having a rearwardlyprojecting narrow extension b formed integral withit, the length being somewhat greater than the breadth of the strip; anearly tubular thimble c, preferably of stiff and resilient metal,having also a lateral terminal piece c, formed from the same piece, anda flat spring d, having a broadened bushing d', formed with two lugs d?.The thimble c is not quite tubular in form, the narrow lip of thethimble being bent inward to give the tube a somewhat spiral section.The stem c thereof is narrowed throughout a portion of its length, sothat a shoulder c2 is formed upon it. The flat spring d has the usualcrimped or curved extremity, designed to conform to the spherical tip ofthe plug and to engage it in such manner as to retain the plug in placein the spring-jack.

In assembling the springjack the fiat spring d is inserted in theopening a2, the broad portion d entering the slot a6. The lugs d2 are inthe plane of the spring when this is putin place, but are subsequentlybent over to enter the recesses a7, extending laterally from the slotsa6. Hence when the spring is in place its transverse movement isprevented by the engagement of the broad portion with the walls of theslot a6, while it is secured against longitudinal movement by the lugsengaging the recesses a7.

The thimble c is placed within the strip from the front thereof, thestem or extension c threading duct a5 until the shoulder c2 comesagainst the floor of the tubular opening a'. The thimble is secured inthis position by a pin e, passing through the wall of the socket andriveted in the thimble c. The thimble b is inserted in the opening a',with its outer edge flush with the strip of springjacks, so as to beaccessible for the usual operation of testing, the extension b from thethimble being threaded through the duct a3 and thence through thesaw-cut a4 to the rear of the spring-jack and being secured in the ductby twisting the broadened terminal through a right angle, so that itcannot be withdrawn from the duct. This thimble also should preferablybe secured in place by means of a pinfthrough the hard rubber.

The plug, Fig. 7, designed for use with this spring-jack comprises theusual spherical tip g and two concentric metallic sleeves g and 92. Thelength of the sleeve g2 should be such that when the plug is fullyinserted in the spring-jack the sleeve will extend through or slightlybeyond the inner end of the thimble b. The sleeve g' is of proper lengthand in suitable position to enter the spring-thimble c and is of suchdiameter as to be grasped with force thereby. The tip g isobviouslydesigned to be thrust under the curved extremity of spring d and to beengaged thereby.

From the foregoing description it will be apparent to one familiar withspring-jacks for telephone-switchboards as usually constructed that thepresent spring-jack is much more simple and compact than any heretoforeproduced, while the operations involved in forming and assembling theparts are of the simplest nature. It will be further apparent that theelectrical connection formed between the spring d and the tip g, thethimble c and the sleeve g', and the thimble b and the sleeve g2,respectively, will be firm and reliable, inasmuch as the first twocontacts are formed between rigid bodies and springs, while the last isformed between a thimble and the sleeve forced against it by thepressure of the springs.

The invention is defined in the following claims:

l. In a spring-jack, the combination with a supporting-plate having atubular opening therein adapted to receive a connecting-plug, of aspring contact-piece of substantially spiral section in the tubularopening, the outer portion of said spiral being rigidly secured to thewall of said opening and the inner end thereof being free to encircleand grasp the plug, substantially as described.

2. The combination with a su pporting-plate having a tubular openingformed therein adapted to receive a connecting-plug, of a contact-pieceof substantially tubular form contained within said opening, saidtubular contact-piece being slit lengthwise from end to end and havingone of its lips bent toward the axis of the opening, the portion notbent in being secured to the wall of the opening lying concentricallytherein, whereby a contact-piece of substantially spiral cross-sectionis produced for making contact with an inserted plug, substantially asset forth.

3. In a spring-jack the combination with a supporting-base having atransverse tubular opening therein, of a contact-ring of substantiallyspiral section in the'forward extremity of said opening, and a flatspring mounted in a nearly axial position in said tubular opening havingits extremity presented before the opening in the said ring to engagethe tip of a plug therein, as described.

4. In a spring-jack, the combination with a base of insulating materialhaving a tubular opening therein, of a tubular contact-thimble securedin the forward extremity of said opening, a second contact ofsubstantially spiral section at the rear of said thimble, the inner endof the spiral projecting toward the IOO IIO

axis of the spring-jack and the other endthereof being secured to theWall of the tubular opening, and a flat spring secured in asubstantially axial position in the said opening, having its extremitypresented before the opening of the spiral contact, and a plug adaptedfor insertion in the spring-jack having three cylindrical contact-piecesregistering with the thimble, spiral contact and the flat spring,respectively, as described.

5. In a spring-jack, the combination with a plate of insulating materialhaving a trans Verse tubular opening therein, the forward portion ofsaid opening being of greater di

